1. Field of the Invention
This invention relates to the manufacture of an electrochemical cell or battery, and more particularly to a method of manufacture thereof to attain an acceptable and stable voltage upon cell assembly.
2. Discussion of the Prior Art
A solid cathode liquid organic electrolyte lithium anode cell or battery has been used as the power source for implantable medical devices. The cathode of such a cell, or other alkali metal anode battery or cell, may have as active material carbon fluoride, a metal oxide, a metal oxide bronze such as silver vanadium oxide, or other suitable material as disclosed in U.S. Pat. No. 4,830,940 by Keister et al, which patent is assigned to the assignee of the present invention and which patent is incorporated herein by reference.
Typically, cells containing cathode active material such as metal oxide, mixed metal oxides, or metal oxide bronze, may when first assembled, display a high voltage which is not stable over time. For example, the voltage of a cell containing the metal oxide bronze silver vanadium oxide as the cathode active material, may degrade from an initial 3.6 or 3.7 volts before reaching a stable voltage of 3.25 volts. This degradation may lead to increased self-discharge in cells resulting in decreased service life, and/or decreased performance under some low rate discharge conditions. In order to avoid these problems, such cells have been placed on load shortly after assembly in order to discharge the high voltage portion of the cells' capacity. However, this practice of discharging the cells after assembly undesirably results in scheduling difficulties in cell production, since every newly constructed cell must be treated promptly, and also results in additional expense for discharging the high voltage portion of each cell's capacity.